Degradation of chlorinated and brominated hydrocarbons by Methylomicrobium album BG8

Abstract

The degradation kinetics of ten halogenated hydrocarbons by Methylomicrobium album BG8 expressing particulate methane monooxygenase (pMMO) and the inhibitory effects of these compounds on microbial growth and whole-cell pMMO activity were measured. When M. album BG8 was grown with methane, growth was completely inhibited by dichloromethane (DCM), bromoform (BF), chloroform (CF), vinyl chloride (VC), 1,1-dichloroethylene (1,1-DCE), and cis-dichloroethylene (cis-DCE). Trichloroethylene (TCE) partially inhibited growth on methane, while dibromomethane (DBM), trans-dichloroethylene (trans-DCE), and 1,1,1-trichloroethane (1,1, 1-TCA) had no effect. If the cells were grown with methanol, DCM, BF, CF, and 1,1-DCE completely inhibited growth, while VC, trans-DCE, TCE, and 1,1,1-TCA partially inhibited growth. Both DBM and cis-DCE had no effect on growth with methanol. Whole-cell pMMO activity was also affected by these compounds, with all but 1,1,1-TCA, DCM, and DBM reducing activity by more than 25%. DCM, DBM, VC, trans-DCE, cis-DCE, 1,1-DCE, and TCE were degraded and followed Michaelis-Menten kinetics. CF, BF, and 1,1,1-TCA were not measurably degraded. These results suggested that the products of DCM, TCE, VC, and 1,1-DCE inactivated multiple enzymatic processes, while trans-DCE oxidation products were also toxic but to a lesser extent. cis-DCE toxicity, however, appeared to be localized to pMMO. Finally, DBM and 1,1,1-TCA were not inhibitory, and CF and BF were themselves toxic to M. album BG8. Based on these results, the compounds could be separated into four general categories, namely (1) biodegradable with minimal inactivation, (2) biodegradable with substantial inactivation, (3) not biodegradable with minimal inactivation, and (4) not biodegradable but substantial inactivation of cell activity.

Development of a Novel Electrochemical Inhibition Sensor Array Based on Bacteria Immobilized on Modified Screen-Printed Gold Electrodes for Water Pollution Detection

“…For this work the following three types of bacteria were selected: (i) Escherichia coli (E. coli, K12 strain) which belong to gram-negative bacteria type generally sensitive to different types of pollutants including heavy metals, pesticides, and hydrocarbons [16], (ii) Shewanella oneidensis (S. oneidensis, MR-1 strain) which belong to gram-positive bacteria and known to be tolerant to heavy metals [17] because of its bio-catalytic-activity towards heavy metals [25], and (iii) Methanotrophic bacteria (Methylococcus capsulatus, Bath strain) gramnegative bacteria which thrive in the presence of some petrochemicals [18][19] because of its bio-degradation-properties [27]. LB (Luria-Bertain) broth was used as a medium for E. coli [20] and S. oniedensis bacterial cell cultures, while M. capsulatus were grown in NMS (Nitrate Mineral Salts) medium [21].…”

Strategies to Optimize Microbially-Mediated Mitigation of Greenhouse Gas Emissions from Landfill Cover Soils

“…Therefore, it is important to know which MMO the methanotrophs are expressing in situ to effectively utilize these cells for mitigation of CH 4 from landfills. (Han, et al, 1999); b (Oldenhuis, et al, 1991); c (Lontoh and Semrau, 1998) 1.6. Factors affecting methanotrophic community structure and activity Little is known how different environmental conditions affect the distribution, numbers and activity of methanotrophs other than Type I and II strains.…”

Characterization of a Mixed Methanotrophic Culture Capable of Chloroethylene Degradation

“…The consortium was grown from soil immersed in nitrate mineral salt (NMS) medium (Whittenbury et al, 1970) at 30°C in batch flasks shaken at 270 rpm in a 1:2 methane-air atmosphere ratio at 1 atm of pressure. The cultures were grown at 30°C to compare the rates of degradation measured here with those collected by others (van Hylckama Vlieg et al, 1996;Han et al, 1999). The culture medium was no more than 15% of the total flask volume to prevent mass transfer limitation of methane and oxygen from the headspace to liquid medium.…”

“…Removal of c-DCE and VC under oxic conditions has therefore also been investigated for bacteria that express mono-or dioxygenase enzymes growing on methane, propane, phenol, ammonia, or toluene (Ensley, 1991;Arp, 1995;Wackett, 1995). Methanotrophs, bacteria that express methane monooxygenase (MMO) for the oxidation of methane, express two forms of the enzyme: the cytoplasm-associated or soluble methane monooxygenase (sMMO) and the membrane-bound or particulate methane monooxygenase (pMMO) (Han et al, 1999). Most known methanotrophs express pMMO.…”

“…The form of MMO being expressed by in situ methanotrophic populations is of great importance for remediation treatment systems, as the oxidation rates of c-DCE, TCE, and VC are orders of magnitude lower than for methanotrophs expressing pMMO than for cells expressing sMMO (Van Hylckama Vlieg et al, 1996;Lontoh and Semrau, 1998;Han et al, 1999).…”